Emergency oxygen supply

Abstract

A portable emergency oxygen supply which may be carried without difficulty by a user and is safe under all conditions. The supply includes a canister containing oxygen-rich gas at relatively low pressure, the canister having a normally-closed valve which is provided with an actuating switch. The valve output is coupled by a feed tube to the interior of an inflatable bellows which is attached to and communicates with a face mask whereby the user is able to repeatedly inhale and exhale the volume of gas enclosed in the bellows, in the course of which he depletes the oxygen contained therein. The oxygen in the bellows is intermittently replenished by operating the switch so that the available oxygen in the canister is fully utilized.

I claim: 
     
       1. An emergency oxygen supply comprising: A. a canister containing oxygen and provided with a normally-closed switch-actuated valve;   B. a mask and bellows sub-assembly constituted by a mask adapted to receive the mouth and nose of a user and to confine breathing to the interior of the mask and an inflatable bellows attached to the mask and communicating therewith;   C. means to feed oxygen from said canister into the bellows and coupled to the output of the valve, whereby when the switch is actuated, oxygen from the canister is fed into and inflates the bellows, to enrich the gas which the user inhales and exhales, and making it possible for the user to breathe the same volume of gas in the bellows until such time as the oxygen therein requires replenishment; and   D. a dome-shaped cap fitting over the top of said canister, said mask being integral with a side wall of said cap and forming a part thereof whereby the bellows attached to the mask is normally confined within the interior of the cap, the side wall of the cap opposed to the mask being provided with a spring-biased trap door that, when the bellows is inflated, is forced open by the expanding bellows to permit the bellows to expand outside of said cap.   
     
     
       2. A supply as set forth in claim 1, wherein said cap is formed of transparent material. 
     
     
       3. A supply as set forth in claim 1, wherein said oxygen in the canister is maintained under relatively low pressure. 
     
     
       4. A supply as set forth in claim 1, wherein a relatively small percentage of carbon dioxide is intermixed with said oxygen.